Add text rendering for Stream Deck buttons with toggle demo

cmd/decktest/main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"fmt"
 	"image/color"
-	"math/rand/v2"
 	"os"
 	"os/signal"
 	"syscall"
@@ -11,6 +10,42 @@ import (
 	"qrun/lib/streamdeck"
 )
 
+var palette = []color.RGBA{
+	{220, 50, 50, 255},
+	{50, 180, 50, 255},
+	{50, 100, 220, 255},
+	{220, 160, 30, 255},
+	{180, 50, 180, 255},
+	{50, 180, 180, 255},
+	{220, 120, 50, 255},
+	{100, 100, 200, 255},
+}
+
+func labelForKey(key int) string {
+	row := key / streamdeck.KeyCols()
+	col := key % streamdeck.KeyCols()
+	switch row {
+	case 0:
+		return fmt.Sprintf("Ch %d\nSelect", col+1)
+	case 1:
+		return fmt.Sprintf("Ch %d\nMute", col+1)
+	case 2:
+		return fmt.Sprintf("Ch %d\nSolo", col+1)
+	case 3:
+		return fmt.Sprintf("Ch %d\nRec", col+1)
+	}
+	return fmt.Sprintf("Key %d", key)
+}
+
+func drawKey(dev *streamdeck.Device, key int, bg color.RGBA) {
+	dim := color.RGBA{bg.R / 3, bg.G / 3, bg.B / 3, 255}
+	dev.SetKeyText(key, dim, color.White, labelForKey(key))
+}
+
+func drawKeyActive(dev *streamdeck.Device, key int, bg color.RGBA) {
+	dev.SetKeyText(key, bg, color.White, labelForKey(key))
+}
+
 func main() {
 	dev, err := streamdeck.Open()
 	if err != nil {
@@ -24,12 +59,12 @@ func main() {
 	dev.SetBrightness(80)
 
 	for i := 0; i < streamdeck.KeyCount(); i++ {
-		r := uint8(rand.IntN(256))
+		col := i % streamdeck.KeyCols()
-		g := uint8(rand.IntN(256))
+		drawKey(dev, i, palette[col])
-		b := uint8(rand.IntN(256))
-		dev.SetKeyColor(i, color.RGBA{r, g, b, 255})
 	}
 
+	active := make([]bool, streamdeck.KeyCount())
+
 	keys := make(chan streamdeck.KeyEvent, 64)
 	go func() {
 		if err := dev.ReadKeys(keys); err != nil {
@@ -43,15 +78,17 @@ func main() {
 	for {
 		select {
 		case ev := <-keys:
-			if ev.Pressed {
+			if !ev.Pressed {
-				fmt.Printf("Key %d pressed\n", ev.Key)
+				continue
-				r := uint8(rand.IntN(256))
-				g := uint8(rand.IntN(256))
-				b := uint8(rand.IntN(256))
-				dev.SetKeyColor(ev.Key, color.RGBA{r, g, b, 255})
-			} else {
-				fmt.Printf("Key %d released\n", ev.Key)
 			}
+			col := ev.Key % streamdeck.KeyCols()
+			active[ev.Key] = !active[ev.Key]
+			if active[ev.Key] {
+				drawKeyActive(dev, ev.Key, palette[col])
+			} else {
+				drawKey(dev, ev.Key, palette[col])
+			}
+			fmt.Printf("Key %d toggled %v\n", ev.Key, active[ev.Key])
 		case <-sig:
 			fmt.Println()
 			return

lib/streamdeck/text.go

@@ -0,0 +1,45 @@
+package streamdeck
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"strings"
+
+	"golang.org/x/image/font"
+	"golang.org/x/image/font/basicfont"
+	"golang.org/x/image/math/fixed"
+)
+
+func TextImage(bg color.Color, fg color.Color, lines ...string) image.Image {
+	img := image.NewRGBA(image.Rect(0, 0, keySize, keySize))
+	draw.Draw(img, img.Bounds(), &image.Uniform{bg}, image.Point{}, draw.Src)
+
+	face := basicfont.Face7x13
+	metrics := face.Metrics()
+	lineHeight := metrics.Height.Ceil()
+
+	totalHeight := lineHeight * len(lines)
+	startY := (keySize-totalHeight)/2 + metrics.Ascent.Ceil()
+
+	for i, line := range lines {
+		width := font.MeasureString(face, line).Ceil()
+		x := (keySize - width) / 2
+		y := startY + i*lineHeight
+
+		d := &font.Drawer{
+			Dst:  img,
+			Src:  &image.Uniform{fg},
+			Face: face,
+			Dot:  fixed.P(x, y),
+		}
+		d.DrawString(line)
+	}
+
+	return img
+}
+
+func (d *Device) SetKeyText(key int, bg color.Color, fg color.Color, text string) error {
+	lines := strings.Split(text, "\n")
+	return d.SetKeyImage(key, TextImage(bg, fg, lines...))
+}